Verify which model you have. It appears to be a Singer. If it is, you can check the serial number against the ISMACS Singer database to learn what model it is and when (sometimes even where) it was made. If you have a Singer 128, say, you might be able to purchase modern bobbins and shuttles online. I ordered some from Amazon. Replacing the slide can be more difficult, but it is critical. You don't want fabric falling into the machine during operation. Serial number for older Singers can be found at the base of the pillar in front. This is what a serial number might look like.

Lovely! It's a Singer model 27, with pheasant decals. You can find a manual for it on the Singer website. Have fun doing the cleanup!